This invention relates generally to frictional resistance to relative displacement of members, and more particularly to controlled frictional resistance to cyclic displacement of one member relative to another.
There is need for improvements in devices which provide frictional resistance to relative displacement of members, considering the difficulty of controlling transitions between static friction (existent before the members are relatively displaced) and sliding friction (existent while the members are undergoing relative displacement). Such transitions occur, for example, during cyclic (back and forth) movement of such members. Experience has shown that the force needed to effect cyclic back and forth movement between frictionally interengaged members tends to increase and then decrease over a range of cycling, under the static and sliding friction conditions occurring during each cycle, as referred to. Such force increases and decreases transmitted through associated mechanism can and do increase the wear, and reduces the lives, of such mechanism.
What is needed is a means to reduce or substantially eliminate such force increase and decrease, needed to cyclically displace one member relative to another over a large number of cycles, which the members are frictionally interengaged.